Remote control and indicating system



April 25, 1944.

A. SUKSDORF REMOTE CONTROL AND INDIGATING SYSTEM Filed Oct. 26, 1940 T t, m /w e vd A nm a A. m

Patented Apr. 25, 1944 REMOTE CONTROL AND INDICATING SYSTEM Alfred Suksdorl, Schenectady, N. Y., assignor to General Electric Company, acorporation of New York Application October 23, 1940, Serial No. 363,032

3 Claims.

My invention relates to a remote control and indicating system, and more particularly to an electrical system for controlling from a transmitting station the condition of a device at a receiving station and for simultaneously indicating at the transmitting station the condition of the controlled device.

An object of my invention is to provide an improved remote control and indicating system 'of the above type which requires only two electrical connections between the transmitting and the receiving station.

It is a further object of my invention to provide an improved remote control and indicating system which permits the condition of a remotely located device to be continuously changed and indicates at the transmitting station the amount of the change.

It is a still further object of my invention to provide an improved remote control and indicating system which permits sequential operation of a. plurality of remotely located devices and indicates at the transmitting station the operation of the remotely controlled devices.

The novel features which I believe to be characteristic of my invention are set forth'with particularity in the appended "claims. My invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof may be best understood a by reference to the following description taken in connection with the accompanying drawing in which Fig. 1 is a diagrammatic representation of a remote control system illustrating my invention and Fig. 2 is a modification of the system shown in Fig. 1.

Referring to Fig. 1 of the drawing a transmit-- ting station indicated generally at H! is connected to a receiving station indicated generally at I l by theconductors I2 and I3. According to my invention the controlled device at the receiving station, which has been illustrated by way of example as a motor operated valve H, is controlled by a switch l5 located at the transmitting station and the condition of the motor driven valve I4 is indicated at the transmitting station by the signal lights l6, l1, and IS. The manner in which my :control system functions to give this result will now be given in detail.

The conductors l2 and ii are connected at the transmitting station to unidirectional potential supply lines I9 and 20 by the conductors 2| and 22 and a double-pole double-throw switch l5 which is arranged so that when the switch [5 is I2 and 13 are energized with a unidirectional voltage of one polarity and when the switch I5 is thrown in the opposite contact engaging position they are energized with a unidirectional voltage of the opposite polarity. The valve M is driven by an electric motor 23 through suitable gearing 24 v rotate in the opposite direction in a well-known in one contact engaging position the conductors manner. A polarized relay 29 having a movable switch member 30 and stationary contacts 3| and 32 is connected across the conductors i2 and 13 at the receiving station ll.' When the polarity of the conductors I2 and I3 is in one direction the movable switch member 30 will move to the left engaging contact 3| and when the polarity is in the reverse direction the switch arm 30 will move to the right engaging contact 32. By connecting the motor fields 21 and 28 to the contacts 3| and 32 and connecting the movable switch member to one side oi the direct current supply line 25, 26 as illustrated in the drawing the motor driving the valve may be made to rotate in one direction or the other depending upon th polarity of the voltage impressed upon the conductors l2 and i3. Thus it will be evident that when the control switch I5 is moved to one contact engaging position the polarized relay 29 will be energized in one direction causing the motor to rotate and open the valve Hi. When the controlled switch I5 i moved to the other contact engaging position, the polarity of the unidirectional voltage ap plied to the conductors l2 and i3 will be reversed causing the polarized relay to be energized and move in the opposite direction which in turn causes the motor 23 to rotate in the opposite direction and close valve I4. When the switch I5 is in the intermediate position, as shown, the motor 23 is deenergized.

In remote control systems of the present type it is desirable to have an indicating device or devices at the transmitting station so that the operator can tell whether or not the desired control has been effected. For this purpose I have provided indicating devices in the form of electric lamps I8, I I and 18 which may be arranged to be sequentially operated during the movement of the valve from the closed to the open position so that the operator can tell at any time the approximate degree of opening of the valve .4

The sequential operation of the indicating lamps 66, it and i8 is accomplished by applying an alternating voltage to the conductors i2 and H3 at the receiving station, the magnitude of which is made dependent upon the degree of opening of the motor valve is. To do this the conductors l2 and 53 are connected to alternating'voltage supply lines 33, as through a voltage divider 35. It will be obvious by reference to the drawing that as the adjustable slider contact 38 of the voltage divider 35 moves to the left the al ternating voltage applied to the conductors i2 and it will be increased and vice versa. ing contact 3d of the voltage divider 35 is attached to a threaded nut 38 which engages a threaded portion 37 of a shaft driven by the valve operating motor 23. Thus the position of the slider as on the potentiometer and the resulting voltage applied to the conductors i2 and 93 at the receiving station are correlated with the degree of opening of the valve it.

The indicating lamps i ii and it are energized from the alternating current supply lines as, at through normally open contacts of voltage sensitive relays indicated generally at 2!, iii. and Q3. The voltage sensitive relays may be of any suitable type and are arranged to become sequentially'energized as the voltage applied across lines M, ie is increased thereby causing the lamps in, ll and it to become sequentially lighted. Ihave shown the voltage sensitive relays as being of the so-called non-linear series resonant type which, in operation, depend on the occurrence of the phenomenon known as ferroresonace. A more complete description of relays of this type may be found in Patent 1,921,786, Suits, granted August 8, 1933, which is assigned to the same assignee as the present application. The relay all comprises a series connected condenser is and iron cored saturable reactor ll having suitable impedances connected to the variable alternating voltage lines dd, lli through a voltage adjusting resistor 33; A solenoid controlling normally open contacts lid in series with the energizing circuit of lamp it isconnectedacross the condenser d5. Whenthe voltage applied across the series connected condenser and reactor reaches a predetermined value, the current in the circuit suddenly jumps to ahigh value resulting in an increased voltage drop across condenser dd causingsolenoid as to pickup closing contacts at to energize signal lamp it. By manipulating the voltage adjuster as, the relay ll can be made to respond to the desired voltage applied across the line i l, 35. When the applied voltage drops below a predetermined value the solenoid 59 drops out opening contacts 5% and deenergizing signal I lamp it. By selecting a proper value of a resistor 5! connected in series with the condenser as and reactor 37, the pick-up and drop-out voltages may be made substantially the same which feature is desirable to avoid error in signal operation.

The construction and operation of relays t2 and is are the same as relay it and corresponding parts have been given corresponding munbers primed to differentiate the relays.

* By. suitably adjusting the voltage adjusters ief id and it" the relays ti, s2 and 33 can be made to pick. up sequentially as the voltage applied to line st, a5 is increased and to drop out sequentially as the voltage is decreased.

As pointed out before the alternating voltage appliedto conductors l2 and i3 is made to correspond to the degree of opening of the valve it. .In some cases the lines 44, 445 may be connected The sliddirectly to the conductors l2 and it at the transmitting station id and the signal lamps it, i!

and it will become progressively energized as the voltage applied to the conductors l2 and it at the receiving station is increased as a result of the opening of valve M Similarly the lamps will become progressively deenergized as the valve It moves to the closed position. In other cases, however, where the wires 82 and it are small gauge and the distance between the transmitting and receiving station is considerable, the voltage drop along the conductors i2 and it; is great and only a relativelysmall alternating voltage is available at the transmitting station which is insumcient to operate the voltage sensitive relays lL-lz, and as. To remedy this I provide a magnetic amplifier to amplify the voltage variations applied to the lines 64 and 5. The amplifier comprises a saturable reactor illustrated schematically at 52 having a direct current input winding 52a and an alternating current output Winding 52b. The alternating voltage appearing across the conductors l2 and is at the transmitting station is rectified by a full wave rectifier 53, which may be of the dry disk copper oxide type, and the resulting unidirectional current is fed to the winding 52a of the saturable reactor 52 with the result that the impedance of winding 52b varies in accordance with the alternating voltage appearing across conductors l2 and 53. A constant voltage transformer 56 having a primary winding connected to the alternating current supply lines as and id is used to en-= ergize the voltage sensitive relays at, 552 and as to avoid error iii operation due to fluctuation in the voltage of line 39, all. One side of the secondary winding of transformer 56 is connected to line it while the other side is connected to the line (i i through the winding 52b of the saturable reactor. The voltage applied to line all, as depends on the impedance of winding 52b which in turn depends on the current in winding 52a and correspondingly the alternating voltage appear ing across conductors l2 and 53. This arrangement amplifies sufiiciently the indicating voltage applied to line id, to properly operate the signal lamps l5, ii and i8.

To prevent the unidirectional voltage applied to line i2, it from interfering with the operation of the alternating current circuits I provide blocking condensers 55 and 56. Also to prevent alter-=- nating current from flowing in the direct current circuits the choke coils 51 and 58 are utilized.

The operation of the remote control and indicating system shown in Fig. 1 will now be described. The control elements shown in Fig. 1 are in the position they assume when the valve Hi is in the closed position. If now the operator at transmitting station Hi desires to open valve l d, the switch i5 is moved to the contact engaging position which causes the polarized relay to become energized in one direction and motor 23 to rotate in a direction to open the valve. As the motor rotates the sliding contact 36 moves to the left know when to open switch l and stop the drive motor 23.

If the operator then moves the switch I5 to the opposite contact engaging position, the polarized relay will be energized in the opposite direction and the motor 23 will rotate in a direction to close the valve I4. The slider 36 then moves back towards its initial position decreasing the alternating voltage applied to the conductors I2 and I3 and consequently causing the signal lamps I6, I1 and IE to become deenergized in a reverse order. The relay 4I may be adjusted so that lamp I6 will go out just as the valve I l reaches the closed position and the operator will know when to return the switch I5 to the center or deenergized position.

It is obvious that a greater or smaller number of signal lamps and relays may be used. However, the greater the number of signal lamps provided, the more accurately the position of the remotely controlled device can be determined by the operator since smaller increments of change can be made to operate a signal lamp. It is also obvious that instead of signal lamps, other wellknown forms of indicating devices could be used such as for example, differently toned bells or buzze'rs, etc. without departing from my invention in its broader aspects.

While I have illustrated the system as being used to control a valve, it will be apparent to those skilled in the art that the system may be used to control many other devices such as, for example, a voltage regulator, circuit breaker, etc. without departing from my invention.

The modification shown in Fig. 2 of the drawing is generally similar to that shown in Fig. 1 and corresponding parts have been given the same reference numerals. However, in the Fig. 2 modification, the control of the device or devices located at, the'receiving station II is accomplished by changing or altering a difierent characteristic of the unidirectional voltage applied to the conductors I2 and I3. In this modification the magnitude of the unidirectional voltage applied to the conductors I2 and I3 at the transmitting station is changed instead of reversing the polarity as in the Fig. 1 arrangement. In addition, a series of voltage sensitive relays responsive to the magnitude of the unidirectional voltage across the conductors I2 and- I3 are used to effect the desired control. Also in thismodiflcation I have shown the remote control system arranged to provide sequence control a plurality of separate electrical load devices I5, I6, and 11;

Coming now to the specific details of the embodiment illustrated in Fig. 2, conductors I2 and I3 are connected to the unidirectional voltage supply lines I9, 20 through a voltage divider 59 having a sliding contact 60. It is evident that by moving the contact 30 the unidirectional voltage applied to the conductors I2 and I3 at the transmitting station may be conveniently varied.

At the receiving station II are located three voltage sensitive relays Ii I, 62, and 63, which may be, as shown, similar in construction to the indicating relays 4|, 42 and 43 described in connection with Fig. 1. These relays are energized from the secondary winding of a constantvoltage transformer 64, the primary winding of which is energized from the alternating current supply line 33, 34 through lines 65, 66. The voltage applied to these relays is controlled by the variable impedance winding 68 of the saturable reactor 61. By connecting the saturating winding 69 of the saturable reactor 61 across the conductors I2 and I3 at the receiving station the impedance of winding 68 and correspondingly the voltage applied to relays BI, 62 and 63 varies in accordance with the magnitude of the unidirectional voltage supplied the line I2, I3 at the transmitting station. By properly adjusting the voltage adjusters I0, I0 and 10" the solenoids II, II and II" of relays 6|, 62, and 63 may be made to pick up sequentially as the unidirectional control voltage is increased and vice versa. The electrical load devices I5, l6 and I! are connected to the supply line 33, 34 through normally open contacts I2, I3, I4 which are controlled respectively by the solenoids II, II and 1|".

Conductors I2 and I3 are connected at the receiving station to the alternating current supply lines 33, 34 through the series connected resistors 15a, 16a, 11a. These resistors are shunted by circuits including the normally open contacts I8, I9 and 86 which are also controlled by the solenoids II, II and II". The remainder of the Fig. 2 arrangement is the same as that of Fig. l.

The operationof the remote control and indicating system shown in Fig. 2' is as follows' If the unidirectional voltage applied to the conductors I2 and I3 is increased by moving the sliding contact 60 to the right, relay 6| picks up closing contacts I2 and IS. The closing of contact I2 connects the load device I5 to the lines 33, 34, and the closing of contact I8 shunts out resistor 15a and thereby increases the alternating voltage applied to conductors I2 and I3. This increased alternating voltage causes relay 4| to pick up energizing the signal light I6 which informs the operator that the load'device I5 has been energized. Similarly if the unidirectional voltage applied to conductors I2 and I3 is increased further relay 62 will pick up closing contacts I3 and 19 to energize load I6 and to shunt out resistor 16a causing energizationof light II. Finally if the unidirectional voltage is increased still further relay 63 picks up closing contacts I4 and 90 to energize load 11 and to shunt out resistor IIa causing energization of light I8. If the unidirectional voltage is then decreased the reverse of the above described operation will take place. Thus the operator can energize load I5 alone, loads 15 and 16 together, and also all three loads I5, I6 and I1 and the energization of these loads will lie-indicated to him by the signal lights I6, I1 and I8.

While I have shown the relays BI, 62 and 63 as controlling the separate load devices they may be used to change the operating condition of a single load device. For example, they might be used to control the speed of an electric motor by changing the resistance of the motor circuit without departing from my invention.

In the remote control and indicating system I have illustrated in Figs. 1 and 2, the unidirectional voltage is applied to the conductors I2 and I3 at the transmitting station to effect the desired control and the alternating voltage is applied to the line at the receiving station to control the operation of the signal lights. However, it is obvious that this arrangement could be reversed whereby the unidirectional voltage would be used to operate the indicating lights and the alternating voltage to effect the desired control.

While I have shown and described particular embodiments of my invention, it will occur to those skilled in the art that various changes and modifications may be made without departing from my invention, and I, therefore, aim in the 4 assasas appended claims to cover all such changes and modifications as fall within the true spirit and said conductors to a source of unidirectional voltage at the transmitting statlon,a relay connected to said conductors at the receiving station responsive to'the polarity of the unidirectional voltage impressed on said conductors at the transmitting station, a reversible motorfor progressively changing the position of said device, .an energizing circuit for said motor including the contacts controlled by said relay arranged so that the direction of rotation of said motor is determined by the polarity of the voltage impressed on said conductors, means independent of the position of said device for connecting said conductors at the receiving station "to a source of alternating voltage, means for progressively altering the mag nitude of the alternating voltage supplied to said conductors in accordance with the position of said device, and a plurality of relays connected at said transmitting station to be responsive to the alter nating voltage across said conductors, said relays being set to respond to progressively difi'erent alternating voltages whereby said relays respond in sequence as the position of the control device progresses, and signal means associated with and controlled by each relay.

2. In a system for indicating at a transmitting station the position of a remote device located at a receiving station, said device being electrically actuable progressively between two extreme positions from said transmitting station, the combination comprising a pair of conductors interconnecting said stations, means including said conductors for controlling said device from said transmitting station, a source of variable voltage connected to said conductors at said receiving station, means controlled by said device for varyill log said voltage progressively as said device is progressively actuated from one extreme position to the other, a plurality of electroresponsive voltage-sensitive signal devices connected at said transmitting station to be responsive to the voltage supplied to said conductors at said receiving station, said signal devices being set to respond to progressively different voltages so that said signal devices respond in sequence as the position of said remote device progresses from one extreme position to the other whereby an operator at the transmitting station may, by observing the condition of energization of said signal devices, determine the position of said remote device.

3. In a system for indicating at a transmitting station the position or a remote device located at a receiving station, said device being electrically actuable progressively between two extreme positions from said transmitting station, the combination comprising a pair of conductors interconnecting said stations, means including said conductors for controlling said device from said transmitting station, a source of variable voltage connected to said conductors at said receiving station, means controlled by said device for varying said voltage progressively as said device is progressively actuated from one extreme position to the other, means located at said transmitting station for indicating the position of said remote device, said indicating means comprising a saturable reactor having a direct current input winding and an alternating current output winding, a source of constant alternating voltage, a plurality of resistors, said alternating current winding, said resistors, and said source of constant alternating voltage being connected in series circult relation, means for energizing said input winding with'a direct current variable in accordance with the voltage supplied to said conductors at said receiving station, a plurality of electroresponsive voltage-sensitive signal devices adjustably connected across diflerent ones of said resistors, said signal devices being set to respond in sequence as said remote device progresses from one extreme position to the othe ED SUKSDORF. 4 

